Every now and then in the webmaster blogosphere and forums, this issue comes up: when a webmaster performs a [site:example.com] query on their website, the number of indexed results differs from what is displayed in their Sitemaps report in Webmaster Tools. Such a discrepancy may smell like a bug, but it's actually by design. Your Sitemap report only reflects the URLs you've submitted in your Sitemap file. The site operator, on the other hand, takes into account whatever Google has crawled, which may include URLs not included in your Sitemap, such as newly added URLs or other URLs discovered via links.

Think of the site operator as a quick diagnosis of the general health of your site in Google's index. Site operator results can show you:

Your Sitemap report provides more granular statistics about the URLs you submitted, such as the number of indexed URLs vs. the number submitted for crawling, and Sitemap-specific warnings or errors that may have occurred when Google tried to access your URLs.

Feel free to check out our Help Center for more on the site: operator and Sitemaps. If you have further questions or issues, please post to our Webmaster Help Forum, where experienced webmasters and Googlers are happy to help.